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Shaanxi Chemical Industry’s Gasification Plant Takes Multiple Measures to Enhance Slurry Concentration to Ensure Efficient and Stable Production Author/Source: Shaanxi Chemical Industry Date: 2021-02-26 Clicks: 1 In ammonia synthesis, high-concentration, qualified water-coal slurry plays a crucial role in ensuring efficient and stable operation of the system. Entering 2021, the gasification plant took various measures to focus on the concentration of water-coal slurry in its production units, aiming to address the production bottlenecks and continuously improve operational parameters. As a result, the concentration of water-coal slurry was increased to over 62.8%, reaching the highest level ever recorded for such concentration; this paved the way for efficient, stable, and long-term operation of the ammonia synthesis system. Control the particle size of the raw coal to meet the requirements for slurry concentration. The hardness and particle size of the raw coal are basic requirements for slurry concentration. When the raw coal has high hardness or large particle size, it is difficult to grind the coal particles fine; as a result, the coal slurry produced has coarse particles, poor stability, and is not suitable for transportation ； When the hardness of the raw coal is low or its particle size is small, the particle size of the resulting coal slurry becomes finer, making it easier to produce high-concentration coal slurry. Starting from the intake of raw coal into the warehouse, the gasification plant strictly controls the quality of the coal supplied; it carefully selects the type, hardness, particle size, ash content, and moisture level of the coal to prevent substandard coal from entering the system from the very beginning. Optimize the grading of the mill rods to change the particle size distribution of the coal slurry. The grading of the grinding rods has a direct impact on whether the particle size distribution of the coal slurry is appropriate; when the type of coal remains unchanged, adjusting the grading of the grinding rods can effectively modify the particle size distribution of the coal slurry. After conducting research, the technical team adjusted the grading of the grinding rods inside the mill; firstly, the original grinding rods made of 65 manganese were replaced with M45 material, thereby increasing the hardness of these grinding rods ； Second, the weight of the grinding rod has been increased; its weight has risen by 5 tons ； Thirdly, steel rods are regularly added to the mill, thereby improving its pulp-making capacity and meeting the requirements regarding the particle size distribution of the coal slurry. Change the mill sealing method to stabilize the slurry concentration. Previously, the mill cylinder was sealed using bolts and gaskets; these gaskets tended to age quickly, requiring frequent maintenance and resulting in a short operational life for the mill. Following research and discussion by the technical team, replacing the gasket with a filler not only provides better sealing performance but also ensures a longer duration of sealing. This effectively reduces the frequency of mill maintenance, extends the operational life of the mill, improves its pulp-making capacity, and stabilizes the coal slurry concentration. Improve coal slurry additives to enhance coal slurry concentration. Water-coal slurry additives can alter the viscosity of the coal slurry during its concentration process, and they determine the fluidity and stability of the slurry. The technical staff at the branch plant promptly adjusted the ratio of additive materials and strictly controlled their usage, ensuring that the viscosity of the coal slurry met the required specifications and thereby enhancing the plant’s ability to produce qualified coal slurry. In addition, the gasification plant also improved the slurry adhesion by installing baffles at the end of the mill drum screens. By adding a recirculation device to perform secondary grinding of the coal slurry and using methods such as producing coal slurry with a fine particle size, it is possible to ensure the production of high-concentration coal slurry. Through these measures, the slurry concentration in the production unit increased from 62.0% in 2020 to 62.8%, and by early February 2021, it had remained stable at this new level of over 62.8%. With the concentration of the coal slurry, the reaction efficiency of the coal slurry in the gasifier improved significantly, resulting in an increase in gas production. The daily output of synthetic ammonia reached new highs, laying a foundation for ensuring efficient and stable production throughout the year.